An Ethernet network can usually support a variety of communicating bit rate modes, such as: 10 Mbps mode, 100 Mbps mode, and 1 Gbps mode.
Furthermore, two Ethernet networks can communicate with each other through the coupling of twist pairs. Under the 10 Mbps and 100 Mbps modes, two Ethernet networks can work properly by simply coupling two twist pairs between the two Ethernet networks; however, under a 1 Gbps mode, four twist pairs have to be coupled between the two Ethernet networks in order to make the two Ethernet networks work properly.
FIG. 1 is a diagram illustrating a prior art wired network. The wired network 100 is an example of the above-mentioned Ethernet network. The wired network 100 comprises a first network device 110 and a second network device 150. Both the first network device 110 and the second network device 150 are capable to communicate under the 1 Gbps mode. Furthermore, both the first network device 110 and the second network device 150 can support communication below 1 Gbps, which is 10 Mbps or 100 Mbps. The first network device 110 comprises a first set of connection ends 120 (which comprise a first connection end 122 and a second connection end 124) and a second set of connection ends 130 (which comprise a third connection end 132 and a fourth connection end 134). Similarly, the second network device 150 comprises a first set of connection ends 160 (which comprise a first connection end 162 and a second connection end 164) and a second set of connection ends 170 (which comprise a third connection end 172 and a fourth connection end 174). Under the 1 Gbps mode, the four connection ends 122, 124, 132, 134 of the first network device 110 have to couple to the four connection ends 162, 164, 172, 174 of the second network device 150 through a pair of twist pairs, then the first network device 110 and the second network device 150 can communicate with each other properly.
More precisely, when the wired network 100 starts to establish a data transmission channel, the first network device 110 and the second network device 150 will first utilize the first set of connection ends 120 and 160 to mutually transmit the link pulse to confirm the communication ability of both devices. When both devices are confirmed to have communication ability under the 1 Gbps mode, and the first network device 110 is assumed to serve as the first network device and the second network 150 is assumed to serve as the second network device. The first network device 110 then utilizes the first and second set of connection ends 120, 130 to transmit an idle pattern to the first and second set of connection ends 160, 170 of the second network device 150. If the second network device 150 successfully receives the idle pattern from the first and second set of connection ends 160, 170, then the second network device 150 also can utilize the first and second connection ends 160, 170 to transmit the idle pattern to the first and second set of connection ends 120, 130 of the first network device 110. Then, the first and second network devices 110, 150 can establish communication under the 1 Gbps mode.
However, for the wired network 100, the physical communicating path between the first network device 110 and the second network device 150 may not conform to the requirement of the 1 Gbps mode. For example, one possible situation is when the first set of connection ends 160 of the second network device 150 is correctly coupled to the first set of connection ends 120 of the first network device 110, but the second set of connection ends 130 of the first network device 110 is not correctly coupled to the second set of connection ends 170 of the second network device 150. Therefore, in the above-mentioned situation, although the first and second network devices 110, 150 can utilize the first set of connection ends 120 and 160 to confirm that both connection ends have communication ability with each other under 1 Gbps mode, the second set of connection ends 130 and 170 are not coupled correctly. Therefore, the first and second network devices 110, 150 still cannot establish the real 1 Gbps communication with each other. Furthermore, at the mean time, the first and second network devices 110, 150 will keep trying to establish the communicating mode of 1 Gbps mode, but will not succeed due to the incorrect connection.